PURPOSE: To assess the impact of prolonged and intense exposure to video display terminals (VDTs) on ocular surface homeostasis. METHODS: 30 subjects limited daily VDT usage to less than 3 h for one week, then extended usage to more than 8 h/day for the next three weeks. Ocular symptoms and signs were evaluated weekly using the Ocular Surface Disease Index (OSDI) questionnaire and clinical examinations. Eyelid margins and meibomian glands were examined, and ocular surface samples were collected for transcriptomic analysis. RESULTS: Average daily VDT time increased from 2.55 ± 0.46 h initially to 11.17 ± 2.45, 11.75 ± 2.63, and 10.89 ± 2.41 h over three weeks. The dry eye diagnosis rate rose from 6.67 % to 51.67 %. Total OSDI score (P = 0.008), symptoms score (P = 0.014), and visual function score (P = 0.002) significantly increased. Mean fluorescein break-up time (FBUT) decreased from 6.46s to 3.08s. Corneal fluorescein staining (CFS) score (P <
0.001) and lissamine green conjunctival staining (LCjs) score (P = 0.036) worsened. Ocular redness index (RI) increased at 1 week and 3 weeks (P = 0.007, P = 0.001). Telangiectasia scores of both upper and lower eyelid margins increased at 3 weeks (P = 0.002, P <
0.001). Meibomian gland orifice blockage worsened (P = 0.014, P = 0.002). Transcriptomic analysis revealed dynamic alterations in ocular surface gene expression, including inflammatory and hormonal responses. MUC5AC and TFF1 genes showed negative correlations with OSDI and conjunctival staining score, respectively. CONCLUSION: Prolonged VDT exposure deteriorates ocular surface symptoms and signs, with significant inflammatory responses and hormonal activity indicating an imbalance in ocular surface homeostasis.